Material level control means for feed hoppers



March 31, 1953 E. E. FIELDS EIAL 2,633,509

MATERIAL LEVEL CONTROL MEANS FOR FEED HOPPERS Filed Nov. 10, 1951 5 Sheets-Sheet l nro/v 6004 05 0/- 41/ NAME? PRESSUAE March 31, 1953 Filed Nov. 10, 1951 if if E. E. FIELDS ET AL MATERIAL LEVEL CONTROL MEANS FOR FEED HOPPERS 3 Sheets-Sheet 2 yii'apffliiz'i Z5,

March 31, 1953 E. E. FIELDS EI'AL 2,633,509

MATERIAL LEVEL CONTROL MEANS FOR FEED HOPPERS I Filed Nov. 10, 1951 3 Sheets-Sheet 5 Patented Mar. 31, 1953 UNITED STATES PATENT OFFICE tmttm LEVEL oo T'rrioL tee FEED HOPPERS' u Ernest E'. Fields',:- Newark, Frank- A. Jo'va', Kearii'y,

and FrankP. Librizzi-, 'Union,'N.' n i snettieirntvettt er 1o, fsitnstitti N6. 55342 4 015111215. (01; zoo-=52) This intefititn jer t'e j t'e 1mprev q means for controlling level ormateriaiin a-nopper or bin from which the material" gravitate's to a place ofuse. v

The invention has for" anob'jeot'to provide n connection with aho'plier or bin used to feed material, espeeialljdiscrete material such as coal, sand, grain,"crusheds tone, ores or the like, to a place of use, imp dved means for maintain 'ing a desired level pjf the material within the hopper or bin eitlfieij automatically by controlling means by which service of replenishment material to the hopperlor bin is accomplished, or by actuating signal means indicative of need for service of replenishment material to the'liopper or bin wlhen levelo'f the material therein becomes dangerously low; or discontinuance of such service'when thele've'l becomes dangerously high, so that an ade'quatevolume of the material can be-eehetanti maintained within the hopper or bin. g V I The invention has' ror aspec'ific object to provide, in combination with'a wall of a hopper or bin, diaphragm controlled valve means,- 'which is" responsive to pressure of material withinithe hopper r binQviheiebY to'fgovern transmission of a pressure fluid-to electrical switch mean adapted to' be actuatedibv"variationo'f the fluid pressure for opening and'clo's'ingf' an electric circuit by which meehenism operativ'ftb supply replenishing material to the hopjgier or bin is conftrolled, or to operate visible oifl audiblesig'nal means indicative of met" ial' level conditions within the hopper orfbin, or 'b'oth. 4 g V q Other obj eets of" this invention will 'be 7 under stood upon reading the followingf description-of illustrative embodiments; of" theinvention; in connection with the accompanying drawings, in

which: p I I c Fig. 1 is an elevational view" of a hopper qu pp d with one.- q m. and arran em [9 material level control"niearisjacjeqrdirrgtothis invention; andfFifg' 2 is" a fragmentary sectional view, taken on lineZ Z'iIi Fig. 1,'b'ut drawnon taken on line 33 mrigg g; but drawn'on a further enlarged scale; said'view showing the diaphragm controlled valve open to, relieve pressure in the pressure fiuidllineiwhich controls a pressure responsivejeleotric switch means; and Fig; 4 is a similar view, showing. the diaphragm controlled Val-V9: 1 9 Pre se f thi h P c t tvunq iatlie dia hra m 1 whs e y;, to render pressure in the pressure fluid line efiecupon the tiesei-e responsive electric switch fiii e M 1 .7

, Fig; 5 is, an elevational view similar to that of lfig. l,-but;sh owing a modified arrangement wh r n: he-ho e is eq ip d with o a highlevel responsive diaphragrn controlled valves tbi p i e v eb tr' l e ec r q c u t er t ting' and; st ppmg'mee ie for serving replenishing i iwiih her a- Sim a he et sl re r c r e o e in the above described views;to indicate correspending" partsi I I H v g Referring to the d' ttwin'gs; more particularly to" rage. 1- to 4' inclusive'th'ereoi, the reference character" l0 indicatesa. hopper which is equippedwith material level control means according to this invention. A wall of the hopper lo which-maybe eithe r its inclinedwall or itsper'pendicular wall, but preferably the latter as shown; is provided with an opening l'l'siiitably located'intermediate its'open top and its bottom discharge end, substantially in the plane of a desired mini'murhlevel below which material" in the hopper is not desired to fall. ngaged with marginal portions" of the wall openin is-an annular frame or'ringji2. This frame-define I2 is provided-in internal extension' from its inner periphery; with aseating flange; i 3 which is entered in the wall opening and which is provided I on it's" iiiner rate with grip ing teeth l4. seated against the flange i3 is' 'a' fieiiibl'ediaphragm memb'ei-it; the inner raeeor' which is ekposedto'th'e interior of the hopper l0 The inner face marginal portions of said diaphragm i5 are gripped by the teeth It "of the seating" flange is; The outer face marginal portionsoi said diaphragm member iii are grippedby the teeth 16 orac e mt ring which" is inse'rte'd within theif'rarne' or ring 52.

Applie'dacro's'sthe' outer face of; the frame or ring I2 is-a"backing';plat 'e"ia'which retains the clampirinfg ill inlgripl ihgwelation to the diaphragm memb'er-"l The" assembly of frame or ring |2-', diaphragm member i5, clampingring 11 and backing plate It is'afiix'ed to the hopper wall by suitable fastening means, such bolts l9',*-'thu's 'operati-vely supporting the diaphragm member v |5 subjectto'engageineht by? thematerial content of the hopper it and to outwardly flexing pressure exerted "thereon by' said material content;- v .7

Formed in connectionwith the backing plate 18; inyalignment .with the center or axis or the diaphragm;member ii 5; is an outwardly project- ,ing externally; sorewthreadedy, tubular throat portion 20. Threaded onto the free end of this throat portion 28 is a closure member or cap 2| having an internally screw-threaded axial opening 22 in its end wall. Threaded through the opening 22 of the closure member or cap 2|, for axial extension into the interior of the throat portion 2G, is a valve housing member 23. This valve housing member 23 is provided with a valve chamber 24 which enters into its inner end, and which terminates in a valve seat 25. The valve seat 25 surrounds a pressure fluid passage 26 which leads to the valve chamber 24 from the outer end of the valve housing member. Movably supported within the valve chamber 24 is a valve member 2'1, the conical inner end portion of which cooperates with the valve seat 25. The exterior end or the valve member 21 is opposed to the diaphragm member 15. Said valve member 2'! is yieldably urged to normal open position by a compression spring 28 which is connected between its exterior end and the inner end of the valve housing member 23. A compression spring 29 is arranged between the end wall of the closure member or cap 2! and the outer face of the diaphragm member l5, and is operative to inwardly flex the diaphragm member so as to relieve closing thrust upon the valve member El when said diaphragm member is relieved from outthrusting pressure of material within the hopper iii. The closure member or cap 2| is provided with a vent opening 38 leading outwardly from the interior of the throat portion 2t. Likewise, the backing plate I8 is provided with a vent opening 3i leading outwardly from the space 32 between the backing plate and the diaphragm member, which space 32 is in communication with the interior of the throat portion 20.

Connected by a suitable union or coupling 33 to the outer end of the valve housing member 23, to communicate with the pressure fluid passage 26 of the latter, is a conduit 34 through which is served a fluid under pressure, such as compressed air, from a source thereof to the diaphragm controlled valve 2?. Connected in communication with the pressure fluid conduit or line 34 is a pressure responsive electrical switch 35. Said switch isoptionally adapted to control the circuit of electrically actuated means for timing the operation of mechanism (not shown) by which replenishment material is served to the hopper Ii], or to control the circuit of electrical audible or visible signal means (not shown) used to indicate material level conditions within the hopper l0.

A pressure fluid volume chamber 36 of suitable capacity is preferably provided for connection in the conduit or line 3 intermediate the switch 35 and the diaphragm controlled valve 21.

In an embodiment of the invention such as shown in Fig. 1, wherein but one diaphragm controlled valve 2? is employed in connection with the hopper l9, assuming that the switch 35 is of a self-closing type adapted to be held in open or circuit interrupting condition by transmission thereto of pressure of the fluid in the conduit or line 34, the operation is as follows:

Assuming that the level of discrete material in the hopper it has fallen below the diaphragm l5, thus displacing the material relative to the latter so that no out-thrusting pressure of said material is exerted against the same, then said diaphragm will assume a normal, substantially non-flexed position, its movement to such position being assured by the inward thrust of the spring 29 (see Fig. 3). Under these conditions,

the diaphragm I5 is withdrawn from the opposed end of the valve member 2'1, so that the spring 28 associated with the latter moves the same outwardly in the valve chamber 24, and away from the valve seat 25, thereby opening communication between the valve chamber 24 and pressure fluid passage 26 and conduit or line 3 3. Under these circumstances, the pressure fluid in the conduit or line 34 leaks away past the open valve member 2i through the valve chamber 24 and throat portion 20, venting to the atmosphere through the vent opening 30 of the closure member or cap 2 i, and also through the vent opening 3! in the backing plate l8 via the space 32 between the latter and the diaphragm. Such venting of the fluid efiects a reduction or drop in the pressure thereof within the conduit or line 34, so that the pressure is substantially reduced below normal, and consequently pressure of the fluid which is effective upon the switch 35 is likewise so reduced as to no longer resist self-closing action of said switch, whereupon the switch closes and completes the electrical circuit by which material replenishment mechanism is put in operation to refill hopper lil, or to operate an audible or visible signal indicative of necessity for material replenishment, as the case may be.

When replenishing material is served to the hopper l 0 and the latter is filled so that the diaphragm I5 is covered thereby, and thus subjected to out-thrusting pressure of the weight of material against the same, said diaphragm will be outwardly flexed (see Fig. 4). Outward flexing movement of the diaphragm [5 will engage the same with the opposed end of the valve member 2?, thereby moving the latter inwardly through the valve chamber 24 against the tension of its spring 28, until said valve member engages the valve seat 25, and thus closes the pressure fluid pasasge 26 against escape of fluid from the conduit or line 34. Under these conditions, the pressure of the fluid in the conduit or line 34 rises to the normal initial selected pressure at which the fluid is served from the source thereof. When such normal initial pressure is restored in the conduit or line 34, the fluid pressure will again become efiective upon the switch 35 so as to open and hold open the same against its self-closing action. When the switch 35 is thus opened and held open, the electrical circuit controlled thereby will be interrupted to stop operation of the material replenishment mechanism, or to discontinue operation of audible or visible signal means, as the case may be.

The above operations will be automatically repeated in accordance with fall and rise of material level within the hopper It.

It will be noticed that two vent openings'30 and 3! the preferably provided for venting the pressure fluid which passes the open valve member 21. The provision of thetwo vent openings is desirable since it prevents trapping of the pressure fluid against the exterior face of the diaphragm is with risk of untimely operation of switch 35. in the event tampering closure of a single vent opening by application thereto of a finger should occur.

The diaphragm controlled valve means is ca.- pable of easy adjustment for regulating its sensitivity and to accommodate its action as may be required by the size of the hopper, weight and consistency of material moving through the hopper, and for timing the effect thrust of the diatats-at phragm l against the valvem'ember 21. Such adjustments can be made by adjusting the position of the valve housing member 23 relative to the closure member or cap 2 I, whereby to desirably space the "opposed end of the "valve memer 2'', when said valve member is in open condition, relative to the diaphragm l5, adjusting the tension of the diaphragm return sprin 29 by turning the closure member or cap in or'out on the throat portion '28, or by'both of these adjusting operations.

As above mentioned it is preferable to provide a pressure fluid volume chamber 38 in the conduit or line 34 between the switch 35 and diaphragm controlled valve 2'1, whereby to prevent too sudden a reduction of pressure at the switch 35 upon opening of the valve member 27. The extra volume of pressure fluid stored in said volume chamber takes time to leak off through the open valve, and consequently reduction of fluid pressure at the switch 35 suflicient to permit operation of the latter is retarded, so that false or premature starting of the material replenishment mechanism is prevented. This is of s ecial advantage in the event, due to a sudden discharge of material from the hopper, a temporary displacement of the material within the hopper from its normal angle of repose should occur and result in momentary withdrawal of material thrust against the diaphragm member before the material reaches the low level at which replenishment is desired to be started.

It will be observed that the back plate IE not only supports the valve means, but also serves as a stop for limiting outward flexing movement of the diaphragm l5, thus preventing application of undue stretching stress thereto, while at the same time preventing spillage of material from the hopper should the diaphragm be accidentally ,l

ruptured.

In the hopper installation as above described but one diaphragm controlled valve means is provided, and this arrangement will serve the intended purposes satisfactorily, especially in connection with hoppers of comparatively small capacity. For hoppers of comparatively large capacity it is desirable to utilize two diaphragm controlled valve means, one operative at a low material level and the other at a high material level, whereby to control level of the material in the hopper between selected low and high level points. An installation of the latter kind is shown in Fig. 5, wherein the hopper is provided with a low level diaphragm controlled valve means A and a high level diaphragm controlled valve means B, each of the same corresponding in detail structure, parts and arrangement to that hereinabove already described. To the low evel diaphragm controlled valve means A is connected a pressure fluid conduit or line 34 which serves a pressure responsive switch that communicates therewith. Said conduit or line 3 1 includes a volume chamber 36 between said switch 35 and the diaphragm controlled valve means A. To the high level diaphragm controlled valve means B is connected a pressure fluid line 3% which serves a pressure responsive switch 35'. In this arrangement, the switch 35, as controlled by the low level diaphragm controlled valve means A, can be utilized to start material replenishment mechanism when material drops to the selected low level within the hopper H3, and the switch 35, as controlled by the diaphragm controlled valve means B, can be utilized to stop the material replenishment mechani's'm when material rises in the hopper I'D to the selected high level. I

In practice, pressure of fluid supplied to the conduits or lines and to the diaphragm controlled valve 'ine'ans i's selected according to'that best adapted for operation of pressure respon- 's'ive switch orswitch'es employed. 7

Having now described our invention, we claim:

-1. Material level control means for a feed hopper comprising a frame mounted around an opening in a wall of the hopper, "a flexible diaphragm secured by the rrame across said hopper wall opening subject to out-thrusting pressure of material contained in the hopper, a backing plate "seciir'ecltb and across the exterior of "said frame in oiitwardly spaced parallel relation to the exterior face of the diaphragm, said backing plate having an externally screw-threaded outwardly projecting tubular throat portion axially aligned with the diaphragm, an adjustable cap threaded on said throat portion, compression spring means between said cap and the diaphragm to exert in-thrusting pressure upon the latter, means to provide a fluid escape passage supported by said cap and having a movable valve member to open and close said passage, a conduit adapted to be supplied with a pressure fluid connected in communication with said passage, an electrical switch means in communication with said conduit and responsive to variation of fluid pressure in the latter, said valve member being adapted to be moved by outward flexing of the diaphragm whereby to close said passage against escape of pressure fluid from the conduit and thus maintain pressure in said conduit and switch means, said valve member being movable to open said passage for escape of pressure fluid from the conduit upon retraction of the outwardly flexed diaphragm and thereby to reduce pressure in said conduit and switch means, and means to vent escaping pressure fluid from the space intermediate the diaphragm and backing plate.

2. Material level control means for a hopper according to claim 1 including a volume chamber connected in the line of the conduit between the switch means and the valved escape passage.

3. Material level control means for a feed hopper comprising a frame mounted around an opening in a wall of the hopper, a flexible diaphragm secured by the frame across said hopper wall opening subject to out-thrusting pressure of material contained in the hopper, a backing plate secured to and across the exterior of said frame in outwardly spaced parallel relation to the exterior face of the diaphragm, said backing plate having an externally screw-threaded outwardly projecting tubular throat portion axially aligned with the diaphragm, an adjustable cap threaded on said throat portion, compression spring means between said cap and diaphragm to exert inthrusting pressure upon the latter, a valve hous= ing member adjustably supported by and extending through said cap and provided with a fluid escape passage, a movable valve member carried by the inner end portion of the housing membar with an end thereof opposed to the exterior face of the diaphragm, a conduit adapted to be supplied with a pressure fluid connected in communication with the fluid escape passage of the housing member, an electrical switch means in communication with said conduit and responsive to variation of pressure in the latter, said valve member being adapted to be moved by outward flexing of the diaphragm whereby to close the fluid escape passage and thus maintain pressure in said conduit and switch means, means to yieldably urge said valve member to fluid escape passage opening position upon retraction of the outwardly flexed diaphragm and thus to reduce pressure in said conduit and switch means, and means to vent escaping pressure fluid from the space intermediate the diaphragm and backing plate.

4. Material level control means for a hopper according to claim 3' including a volume chamber connected in the line of the conduit between the switch means and the valve housing member.

ERNEST E. FIELDS. FRANK A. JOVA. FRANK P. LIBRIZZI.

8 .REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,769,910 Ponsonby et a1 July 1, 1930 1,977,228 Carter Oct. 16, 1934 10 2,318,355 Bailey May 4, 1943 2,331,208 Ludi Oct. 5, 1943 

